tests: show the number of parallel jobs used while testing

cmd/tools/modules/testing/common.v

@@ -7,6 +7,7 @@ import benchmark
 import sync.pool
 import v.pref
 import v.util.vtest
+import runtime
 
 const github_job = os.getenv('GITHUB_JOB')
 
@@ -233,6 +234,7 @@ pub fn (mut ts TestSession) test() {
 	remaining_files = vtest.filter_vtest_only(remaining_files, fix_slashes: false)
 	ts.files = remaining_files
 	ts.benchmark.set_total_expected_steps(remaining_files.len)
+	ts.benchmark.njobs = runtime.nr_jobs()
 	mut pool_of_test_runners := pool.new_pool_processor(callback: worker_trunner)
 	// for handling messages across threads
 	ts.nmessages = chan LogMessage{cap: 10000}
@@ -266,6 +268,7 @@ fn worker_trunner(mut p pool.PoolProcessor, idx int, thread_id int) voidptr {
 		p.set_thread_context(idx, tls_bench)
 	}
 	tls_bench.no_cstep = true
+	tls_bench.njobs = ts.benchmark.njobs
 	mut relative_file := os.real_path(p.get_item<string>(idx))
 	mut cmd_options := [ts.vargs]
 	mut run_js := false

vlib/benchmark/benchmark.v

@@ -21,6 +21,7 @@ pub mut:
 	nfail           int
 	nskip           int
 	nexpected_steps int
+	njobs           int
 	cstep           int
 	bok             string
 	bfail           string
@@ -200,7 +201,15 @@ pub fn (b &Benchmark) total_message(msg string) string {
 	if b.nskip > 0 {
 		tmsg += term.colorize(term.bold, term.colorize(term.yellow, '$b.nskip skipped')) + ', '
 	}
-	tmsg += '$b.ntotal total. ${term.colorize(term.bold, 'Runtime:')} ${b.bench_timer.elapsed().microseconds() / 1000} ms.\n'
+	mut njobs_label := ''
+	if b.njobs > 0 {
+		if b.njobs == 1 {
+			njobs_label = ', on ${term.colorize(term.bold, 1.str())} job'
+		} else {
+			njobs_label = ', on ${term.colorize(term.bold, b.njobs.str())} parallel jobs'
+		}
+	}
+	tmsg += '$b.ntotal total. ${term.colorize(term.bold, 'Runtime:')} ${b.bench_timer.elapsed().microseconds() / 1000} ms${njobs_label}.\n'
 	return tmsg
 }